JPS6080139A - Optical disk record reproducer - Google Patents

Abstract

PURPOSE:To obtain a satisfactory disk record reproducer by giving improvement to a control signal generating circuit part when both focusing and tracking servo systems are converted into an IC respectively so that the number of input terminals of these ICs is reduced as less as possible. CONSTITUTION:When KP1' and KP2' are supplied from a compound control signal generating part A, switches 13 and 12 are selectively turned on. Therefore prescribed currents I1 and I2 are supplied to a reverse input terminal (-) of an operational amplifier 17 via a current source 14 or 11. At the same time, a kick pulse KP0 is delivered from an output terminal OUT9. The upper and lower levels of peak voltage can be set at a fixed value with an ordinary resistance and according to the accuracy of currents I1 and I2 without using an exclusive diode, etc. Thus the number of input terminals is reduced as less as possible and a pickup can be shifted accurately and in a short time.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an optical 7”4 record reproducing device,
In particular, it relates to improvements in the control signal generation circuit section.

[Technical background of the invention and its problems]

Conventionally, in an optical disk record reproducing apparatus using radar light, a focus servo and a tracking servo are applied to the pickup in order to perform the reproducing operation satisfactorily.

Each servo system as mentioned above is for servo on/off,
The sensor requires various control signals, such as for key switching, keys for fast-forward pickup υ search, and for generating r i<' pulses.

For this reason, conventionally, a microcomputer used as a control signal generation circuit outputs the various control signals described above at appropriate timings.

In this case, since each of the above-mentioned servo systems itself is composed of discrete circuits, six control signals are supplied through a large number of switch circuits connected to the output port of the microcomputer.

However, in recent years, most of the parts of each servo system mentioned above are becoming so-called one-chip ICs, but even in this case, if you try to adopt the same connection relationship as before as mentioned above, the servo system will The number of pins required for a commercial IC is the same as the number of output ports of a microcomputer, resulting in an IC with an extremely large number of pins, which has been a major problem when attempting to implement an IC.

Also, since there are limits to the output ports of a microcomputer, if a large number of output ports are used only in the servo section, even if the microcomputer itself has the internal capacity, it will not be possible to control other parts. There also tends to be a problem that the device becomes unusable.

Further, in the conventional device, there is a problem in that the kick pulse generation circuit that generates the kick pulse based on the control signal for kick pulse generation obtained from the microcomputer becomes expensive.

In other words, the kick noggles here are used to perform a fast-forward search using the pickup, by swinging the objective lens provided in the pickup in the radial direction of the disk, thereby generating a constant amount of noise sufficient to jump over a predetermined number of tracks. The positive (upper) pulse part has a certain magnitude, and the negative (lower) pulse part has a certain magnitude that is sufficient to apply a brake to the objective lens and stop it as quickly as possible.
This is because the peak voltage of each of the upper and lower pulse portions must be kept constant.

The reason for this is that if the upper and lower peak voltages of the kick pulse are different, even if the microcomputer outputs a generation control signal that correctly calculates the width of the kick pulse, it will not reach the target track accurately. If you go too far and take a long time to converge, you will not be able to carry out accurate pickup and delivery as quickly as possible.

FIG. 1 shows a conventionally known kick pulse generation circuit, in which input terminals (INI) and t(INI) are connected to a microcomputer (not shown) to which first and second pulses are connected.
Control signal for kick pulse generation (KPI)
, (KP2) are supplied.

Here, the first kick pulse generation control signal (
KPI) is used to generate the upper pulse part of the kick pulse as described above, and the second kick pulse generation control signal KP is also used to generate the lower pulse part. And, the first and second kick pulse generation control signals (KP) t(xpz) supplied to the input terminals (INI) and (INI) are connected to a resistor (R1), respectively.
), (R2) and diode (DI).

(D8) and the Zener diode (ZDI), then input resistance and feedback resistance (R
8) to (R6) to the non-inverting input terminal ←) and the inverting input terminal (to) of the operational amplifier (opt).

As a result, depending on the first and second kick pulse generation control signals (KPI) and (KP2) input from the output terminal (OUT), the former has a constant positive voltage, and the latter has a constant positive voltage. In this case, a kick pulse having a constant negative voltage is derived.

However, in such conventional kick pulse generation circuits, in order to keep the upper and lower peak voltages of the generated kick pulse constant, a diode or Zener diode is required, and the resistance used therein is also expensive. Since it had to be used, it was inevitably expensive.

Furthermore, there was also the problem that the output offset became large.

[Purpose of the invention]

Therefore, this invention was made in view of the above points, and its purpose is to reduce the number of input terminals as much as possible when implementing an IC for a focus servo system and a tracking servo system. An object of the present invention is to provide an extremely good optical disk record reproducing device in which a control signal generating circuit section is improved so as to be able to perform the following functions.

[Summary of the invention]

That is, the optical disc record reproducing apparatus according to the present invention is an optical disc record reproducing apparatus having a focus servo system and a tracking servo system for controlling a pickup, in which the pickup is skipped by a B1 constant number of tracks. Synthesis of a control signal for generating a kick pulse sufficient to send and a control signal for imparting hysteresis characteristics to the tracking servo system to generate other control signals for each of the servo systems to control the system. It is characterized by comprising a control signal generation section.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings.

That is, in FIG. 2, (iN, ), (IN, ,
) are the first and second kick noise generation control signals s (KP i ) and (K
P2) is an input terminal supplied from a microcomputer (not shown).

Further, (INS) is an input terminal to which an o-left signal (HYS) for obtaining a hysteresis characteristic, which will be described later, is also supplied from a microcomputer (not shown).

Here, the control left signal (HYS) for giving hysteresis characteristics is used to expand the normal control range by applying hysteresis characteristics to the tracking servo characteristics when the tracking servo system is on. belongs to.

And the above input terminals (INI), (IN!).

Each control signal supplied to (INs) constitutes a composite control signal generation section (A), and each input level (CMOS level: 1 (=5V, L=OV)
The signal is supplied to a buffer circuit 1.2.3 for converting the ECL signal to an ECL level (CML level: H=5V, L=4.7V).

Here, the outputs from the buffer circuits 1 and 2 are supplied to one end and the other end of the input of the OR circuit 40, respectively, and are supplied to one end of each input (however, negative logic input) of the OR circuits 5 and 6. It is designed to be supplied accordingly.

Further, the output from the buffer circuit 3 is commonly supplied to the other end of each of the OR circuits 5 and 6, and one end of an input of an OR circuit 80 and one end of an input of an OR circuit g (described later). However, the output terminal (QTJ'l') of the control signal for hysteresis characteristic (HYS') is
, ), and is also supplied to an output terminal (0UT5) of a tracking servo key-up control signal (TSGUP) via a level shift circuit 10a to be described later.

Further, the output from the OR circuit 4 is supplied to the other input terminal of the OR circuit 8 and the other input terminal (however, a negative logic input) of the OR circuit 9, and is also supplied to the other input terminal of the OR circuit 9 (however, a negative logic input), and is also supplied to the other input terminal of the OR circuit 9 via a level shift circuit 10b, which will be described later. Tracking servo off control signal (TSGOF) output terminal (0UT4
).

Further, the outputs from the Mair circuits 6, 6 are supplied to one input terminal and the other terminal (both are negative logic inputs) of an OR circuit 7, respectively, and a level shift circuit 10c, which will be described later.

Control signals (K, P1') for generating kick pulses are transmitted through 10d (both of which are negative logic manual inputs).

(Kpz) each output terminal (OUT, ), (0UT
2) is provided correspondingly.

Here, the output from the OR circuit 7 is passed through a level shift circuit lθe, which will be described later, to an output terminal (0FSW) of an onset correction circuit switch-on control signal (0FSW), which will be described later.
OUT, ).

Each output from the OR circuit 8.9 is sent to a level shift circuit 10fil-ρg, which will be described later.

(However, both are negative logic inputs), the former is connected to the normal play control signal (PLAY) output terminal (0UT3), and the latter is the focus servo gain up control signal (FSGUP) (D
The signal is supplied to the output terminal (,OUT,).

Here, voltages suitable for each level shift circuit 10a to troll (for example, -2VBE level: H=3.6V, L
= 3.3V).

And the above output terminals (0UT1), (OUT2)
The level shift circuit 10c is derived via the level shift circuit 10c.

Each output from 10d (KP1'), (KP, /
) constitute a kick pulse generating section (1), each one end of which is connected in common, and each other end connected to a negative power supply (Vr+g
) and the positive power supply (Vcc) for controlling the first and second analog switch circuits 13 and 12 connected to each other.

Here, the first and second analog switch circuits 1
3.12 is connected to the inverting input terminal (to) of an operational amplifier 17 which has a feedback resistor 15 and whose non-inverting input terminal (g) is grounded via a resistor 16.

The output terminal of the operational amplifier 12 is a kick pulse (
It is connected to a predetermined part of a tracking servo system (C), which will be described later, via an output terminal (OUT, ) of the KPO).

Here, the tracking servo system (C) is a tracking error signal output amplifier 18 to which a tracking error signal based on, for example, a phase difference (time difference) method is supplied via a pickup (not shown), a 7-point detector, a head amplifier, and a tracking error signal generation section. The tracking error output signal ('rso) from the output terminal (OUT
,. ) to a phase compensation circuit 19, and the output from this phase compensation circuit 19 is supplied via an output amplifier 20 to a tracking coil 24 for driving an objective lens of a pickup (not shown).

In this case, the output amplifier 20 has its inverting input terminal (c) connected to the output terminal (OUT, ) of the kick pulse generation section (B) via a resistor 2, and is grounded via a resistor 22. The output terminals (OUT, ) to (OUT8) of the composite control signal generating section (A) are connected to the output terminals of the synthesized control signal generating section (A) through the resistor 23, respectively. The signal is supplied as a control signal for each analog switch circuit provided in a predetermined portion of the tracking servo system.

In the above explanation, most of the composite control signal generation section (A), kick pulse generation section (5), and the focus servo system and tracking servo system (not shown) are subject to one-chip IC implementation. In this case, each output terminal (0UT1) mentioned above
~(OUT, ), etc. are actually connected to predetermined parts inside the IC.

In the above configuration, the input terminal (INl).

(IN2), (INS) from a microcomputer (not shown) for generating the first and second kick pulses (KPI)p(KP2) and a control signal for imparting hysteresis characteristics (HY
S) are respectively shown in Figure 3(b).

Assuming that the timing waveforms shown in (C) and (a) are given, the respective output terminals (OUT, ) to (OUT, Each control member Jgr (KP□') takes a timing waveform as shown in [Yes]).

(KP,' ), (PLAY), (TSGO
F ), (,TSGUP).

(0FSW)Z-jbi (FSGUP), (HY
S”) will be derived.

Since the synthesis control unit (A, ), which acts like a power supply, can generate eight output control signals with three input control signals, it is necessary to convert this into an IC. This allows the number of input terminals to be reduced as much as possible.

That is, as is clear from Fig. 3, in the kick state, (1(P, ), (KP, ), (J(
YS) are input as H level independently, and when (KPs) and (KPg) are input, the tracking servo system is turned off while the kick pulse (KPO) described later is output. No good ('fs
GOF) is output, and at the same time, a signal (0FSW) for operating an onset correction circuit, which will be described later, is output.

In addition, in the above, the offset correction circuit is designed to prevent an offset from occurring during the search when the pickup objective lens is tilted in the search direction. This is to prevent convergence from taking too long.

After this, when < HYS ) is input manually, a signal to raise the dyne of the tracking servo thread (TSGUP) is output in order to speed up the convergence of the tracking servo system, and a hysteresis characteristic is added to the tracking error signal. No (・Hys',) will now be output.

In addition, in the focus search state (initial state with a disc set, etc.), (KYs) and KPl (or K
P, is also acceptable) are input at the same time. In this case, the kick pulse (KPO) is not output and the above (TSGO)
F), (TSGUP) and focus servo thread key 8in raise (FSGUP) are now output.

Next, to explain the operation of the kick pulse generation section (B), when (KPI) r (KP2) is supplied from the above-mentioned composite control signal generation section (A), the first
And by selectively turning on the analog switch circuit 13.12 of gp 2, r'9
r Constant current (IS).

Since (k, ) begins to flow out or flow in, a kick pulse (Kpo) as shown in the third diagram is output from the output terminal (OUT, ).

According to such a kick pulse generating section (B,), in order to make the upper and lower peak voltages of the kick pulse constant, unlike conventional methods, a diode or a Zener diode is not used, and the resistance is not so large. In addition, there is no need to use a top-of-the-line item, and the glaze can be determined simply by the electric current (work) and (I2), so the structure can be made simpler and cheaper, and by extension 'uJ. This makes it possible to perform accurate pickup feeding in a short period of time.

Especially when trying to implement IC, use current source 1.

This is because as long as you ensure the pairability of the resistors and l transistors that make up 14, you can easily test the current (it) y (■,) with a high degree of shielding. .

However, since the output offset is approximately determined only by the input offset m pressure of the operational amplifier 17, p is also smaller than the conventional one.
can be reduced.

FIG. 4 shows a specific example of the kick pulse generating section (B), in which a two-phase relationship is assumed (KP, ').

(KP□'/) and (KP2> , (Kl'2'/
) is used. And the transistor (Ql), (
qt ) is a current generating section that is in phase with the current source 14, and this current min - trannostar CQl ), (Q
4) and (Qm)i via performance J1. i・dl-device 12
The transistors (Qe) and (Qt) that cause the current to flow from the inverting input terminal ←) of the current source 1
In the ``1 mud (I,) generating section corresponding to 1, this is made to flow directly into the inverting input terminal of the operational amplifier NOR.

It should be noted that this invention is not limited to the embodiments described above and shown in the drawings, and may be modified or overused without departing from the gist of the invention.

[Efficacy of invention]

In other words, as detailed above, according to the present invention, the control signal generation circuit was designed so that the number of input terminals could be reduced to i'' in addition to using ICs for the focus servo system and the tracking servo system. It becomes possible to provide an extremely good optical disc record reproducing device with improved parts.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing a kick pulse generation circuit used in a conventional optical disc record playback device, and FIGS. 2 and 3 are an embodiment of an optical 7” 4-score restraint device according to the present invention. FIG. 4 is a configuration explanatory diagram showing a specific example of the kick pulse generation section used in FIG. 2. (A)... - Synthesis control No. 48 conversion section, (engineering)...kick pulse generation section, (C)...tracking servo system.

Claims (1)

[Claims] In an optical disc record playback device comprising a focus servo system and a tracking servo system for controlling a pickup, a control signal for generating a kick pulse sufficient to send the pickup over a predetermined number of tracks and the tracking servo system. An optical disc record playback device comprising: a composite control signal generating section for synthesizing a control signal and a control signal for imparting hysteresis characteristics to generate other control signals for controlling each of the servo systems. .